Early detection of cardiac ischemia (CI) is important for diagnosis and treatment of coronary artery disease (CAD). CI is usually first observed as changes in ECG's ST segment during exercise. However, there is an extensive body of literature showing that the ST segment change is relatively insensitive and only a moderately specific CAD predictor. Hence, most clinicians refer patients for more expensive and labor intensive radioisotope imaging. A simpler, inexpensive and reliable technology for detecting CI in an asymptomatic population would open the door to early diagnostics of CAD through mass cardiac screening and better management of CAD patients. Mediwave Star Technology (MSTI) pilot studies revealed that heart rate variability (HRV) follows a hysteresis pattern during a proprietary quasi-stationary there-and-back exercise protocol. We propose to use this phenomenon as a basis for a simple inexpensive test using commercially available digital heart rate monitors. MSTI in collaboration with Cleveland Clinic Foundation has just completed data collection in a blind clinical study involving 260 patients and initially aimed at comparison of our QT-RR hysteresis technology with radioisotope imaging. We propose to reprocess these data to assess specificity and sensitivity of our HRV hysteresis method. This will open up a new avenue for a simple and inexpensive non-invasive tool for early diagnostics of CI in mass screening of asymptomatic population.